Sorption of water alkalinity and hardness from high-strength wastewater on bifunctional activated carbon: process optimization, kinetics and equilibrium studies

Abstract

Sorption optimization and mechanism of hardness and alkalinity on bifunctional empty fruit bunch-based powdered activation carbon (PAC) were studied. The PAC possessed both high surface area and ion-exchange properties, and it was utilized in the treatment of biotreated palm oil mill effluent. Batch adsorption experiments designed with Design Expert(®) were conducted in correlating the singular and interactive effects of the three adsorption parameters: PAC dosage, agitation speed and contact time. The sorption trends of the two contaminants were sequentially assessed through a full factorial design with three factor interaction models and a central composite design with polynomial models of quadratic order. Analysis of variance revealed the significant factors on each design response with very high R(2) values indicating good agreement between model and experimental values. The optimum operating conditions of the two contaminants differed due to their different regions of operating interests, thus necessitating the utility of desirability factor to get consolidated optimum operation conditions. The equilibrium data for alkalinity and hardness sorption were better represented by the Langmuir isotherm, while the pseudo-second-order kinetic model described the adsorption rates and behavior better. It was concluded that chemisorption contributed majorly to the adsorption process.

Adsorption characteristics of Pb(II) using biochar derived from spent mushroom substrate

“…When R L = 0, adsorption is irreversible; when 0 < R L < 1, adsorption is favorable; when R L = 1, adsorption is linear; and when R L > 1, adsorption is unfavorable. The R L values of the SMS-derived biochars were in the range of 0.001–0.04 (between 0 and 1), implying that Pb(II) adsorption onto the SMS-derived biochars is favorable 42 . Studies have shown that a Freundlich constant, n, between 1 and 10 indicates favorable adsorption, and that the interactions between biochar and heavy metal ions are stronger when the n value is higher.…”

Kinetic, Isotherm and Equilibrium Study of Adsorption Capacity of Hydrogen Sulfide-Wastewater System Using Modified Eggshells

“…The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were applied to determine the suitable adsorption isotherm model for this process [44][45][46][47]. The isotherm models can also be used to demonstrate how the adsorption molecules are distributed between the solid phase and the liquid phase and to estimate the equilibrium time.…”

Differences in Neonicotinoid and Metabolite Sorption to Activated Carbon Are Driven by Alterations to the Insecticidal Pharmacophore

“…Electrostatic differences between neonicotinoids and their metabolites may also impact sorption to black carbon. Following the loss of the electronegative pharmacophore (nitro-/cyano), neonicotinoid metabolites gain a more positive functional group that may subsequently impact sorption to activated carbon via cation coordination (cation bridging) , or π–π/π + –π interactions. ,, These potential impacts on sorption may be further complicated by water chemistry (e.g., water hardness/alkalinity, dissolved organic carbon, pH, and temperature) due to sorption site blocking, − charge shielding, − or competition. ,, Thus, alteration of the neonicotinoid pharmacophore not only changes organism receptor binding ,, and reactivity with chlorine (as we previously demonstrated) but may also impact sorption in natural and engineered systems.…”